Electronic musical instrument

ABSTRACT

An electronic musical instrument comprises a plurality of tone signal synthesizing circuits connected to a keyboard section in parallel with each other and means for combining the outputs of said tone signal synthesizing circuits. The tone signal synthesizing circuit comprises a series connection of a voltagecontrolled oscillator, a voltage-controlled filter, and a voltage-controlled amplifier; a first, a second and a third waveform generator for supplying controlling voltage waveforms to the oscillator, the filter and the amplifier, respectively, for controlling the tone pitch, the tone coloring and the envelope of the tone signal; and a waveform controlling circuit for supplying information variables for determining the shapes of the controlling waveforms to the waveform generators. The outputs of the tone signal synthesizing circuits are combined to supply an output tone signal provided with coupler effect. Upon depression of any single key, said plurality of tone signal synthesizing circuits are rendered operative to produce a music sound which is a mixture of a plurality of different tones.

United States Patent 1191 Hiyoshi Sept. 2, 1975 1 1 ELECTRONIC MUSICALINSTRUMENT [75] Inventor: Teruo l-Iiyoshi, Hamamatsu, Japan [73]Assignee: Nippon Gakki Seizo Kabushiki Kaisha, Hamamatsu, Japan 22Filed: Apr. 16, 1974 21 Appl. No.: 461,417

84/1.13, 1.19, 1.22, 1.24-1.27, DIG. 2, DIG. 9, DIG. 20, 1.17, DIG. 8

3,767,833 10/1973 Noble ct a1. 84/].01 3,786,166 1/1974 Mieda 84/1.0|

3,801,721 4/1974 Bungcr 84/1.l9

3,809,791 5/1974 Uchiyama 84/124 3,818,115 6/1974 Hirano 84/].24

3,828,110 8/1974 Colin 84/1.0l

R27,983 4/1974 Stearns 84/1.01

Primary ExaminerStephen J. Tomsky Assistant ExaminerStanley J. WitkowskiAttorney, Agent, or FirmCushman, Darby, & Cushman [5 7 ABSTRACT Anelectronic musical instrument comprises a plurality of tone signalsynthesizing circuits connected to a keyboard section in parallel witheach other and means for combining the outputs of said tone signalsynthesizing circuits. The tone signal synthesizing circuit comprises aseries connection of a voltage-controlled oscillator, avoltage-controlled filter, and a voltagecontrolled amplifier; a first, asecond and a third waveform generator for supplying controlling voltagewaveforms to the oscillator, the filter and the amplifier, respectively,for controlling the tone pitch, the

[56] References Cited tone coloring and the envelope of the tone signal;and

UNITED STATES PATENTS a waveform controlling circuit for supplyinginforma- 288 904 H966 Gem 0 84/1 0] tion variables for determining theshapes of the con- 5 H966 84/l:26 trolling waveforms to the waveformgenerators. The 3:538:804 11 1970 George ..s4/1.01 outputs of the toneSignal synthesizing Circuits are 3,557,295 1/1971 Adachi 84/].19 xombined to supply an Output tone signal provided 3,570,357 3/1971Adachi... 84/126 with coupler effect. Upon depression of any single3.571. 1 3/1971 Ada him 84/1.13 key, said plurality of tone signalsynthesizing circuits 3582530 6/197 l--- 84/136 are rendered operativeto produce a music sound 3'609203 9/1971 84/10] which is a mixture of aplurality of different tones. 3,614,288 10/1971 Amano 84/].01 X3,626,078 12/1971 Sekiguchi 84/124 6 Claims, 8 Drawing Figures 20 /3uFIRST VCO VCF VCA ARRAMSEMENT r 4 f r WAVEFURM WAVEFGRM ENVELOPE 5 l"GEN GEN l" CONTROL 1 l 6 7 8 wAvEFoRM CCNTROLLING KEYBOARD CKT SECTION3b 4b 2 VCO i VCF VGA 1 I I 2b ,3b 4b WAVEFORM WAVEFORM ENVELOPE 5b FGEN F GEN I CONTROL i l 6b WANGEMENT WAVEFORM CONTROLLING CKTPATENTEUSEP 2mm R 902 39s SHEET 2 OF 5 F IG. 2A

ATTACK LEVEL NORMAL LEVEL INITIAL LEVEL CuT-OEF LEVEL KEY DEPRESSED ZQEE SECOND ATTACK FIRST D CA DECAY E Y TIME 38 POWER 3 SUPPLY 39 SCHMITTTRIGGER HIGH INPUT OUTPUT 43 IMPEOANCE CONVERTER BUFFER AMPL N N\ I 5336 VOLTAGE SIGNAL CONTROLLING VOLTAGE FROM KEY sEC- WAVEFORM TION 1ELECTRONIC MUSICAL INSTRUMENT BACKGROUND OF THE INVENTION rality ofsynthesizer circuits to obtain coupler effect by simultaneouslyproducing a plurality of different tones for a single depressed key.

2. D escription'of the Prior Art Conventional electronic musicalinstrument which is now used is provided with tonesou'rce circuitsincluding oscillators and freque ncy dividers for producing frequencysignals corresponding to each of the tone pitches for the depressedkeysof the keyboard. Such a frequency signal is used as thetonesourcesignal. The tone source signal is selectively coupled to oneof plural sets of filter circuits with different characteristics toeffect tone coloring. Thus, a musical tone signal with a predeterminedtone pitch and a predetermined tone color is provided The musical tonesignal is then supplied to a sound-producing divice such as acombination of an amplifier and a speaker system to produce the soundsof music being played. y

In such a known electronic musical instrument, how ever, the tone sourcesignal derived corresponding to the operation of a key of the keyboardis a signal with a given frequency'corresponding to the tone pitch forthe depressed key of the keyboard and is formed with reference to saidfrequency from the time the key is depressed to the time this key isreleased. The tone signal is synthesized by appropriately selectingharmonic components of such'a signal. Accordingly, the performance soundproduced'from such a known electronic musical instrument tends to bemonotonous and cannot be accepted as being a truly enjoyable andpleasant musical sound, rich in musical-interest. In any natural musicalinstrument, the tone pitch and the tone color of a musical sound ofproduced are exposed to subtle variationsfrom the commencement till thetermination of the generations of the musicalsound, and thereby fine,exquisite expression of musical sound rich in naturalness is obtained.However, it is very difficult to express effectively the subtlevariations in tonepitch and tone color by the conventional electronicmusical instrument. a i

The present invention is intended to improve the performance of theknown electronic musicalinstrument by eliminating the aforesaiddrawbacks of such instrument.

SUMMARY OF THE INVENTION It is. therefore, the object of the presentinvention to provide an electronic musical instrument of a synthe- Sizertype which comprises a plurality .of synthesizer circuits to obtaincoupler effect by simultaneously prodticihg a plurality of differenttones for a single depressed key. I According to an embodiment ofthisinvention, there is provided an electronic musical instrumentcomprising: a playing keyboard section including a plurality of keys forproducing awoltage signal determining the tone pitch ofa depressed key;at lcast one musical tone signal synthesizing arrangement comprising aplurality of sub-arrangements connected to said playing keyboardsectionin parallel with each other, and combining means for combining theoutputs of said subarrangements, each of said sub-arrangements includinga voltage-controlled variable-frequency oscillator connected to thekeyboard section and generating a tone signal corresponding to saidvoltage signal, a voltagecontrolled frequency-variable filter connectedto said voltage-controlled frequency-variable oscillator, a firstcontrolling waveform generator connected to said voltage-controlledfrequency-variable oscillator for generating a controlling voltagewaveform which controls the frequency of the tone signal generated fromsaid oscillator, a second controlling waveform generator connected tosaid voltage-controlled frequency-variable filter for generating acontrolling voltage waveform which, in turn, controls the cut-offfrequency of said filter, a waveform controlling circuit connected tosaid first and said second waveform generators for supplying informationvariables for determining the shapes of said controlling waveforms.

BRIEF DESCRIPTION OF THE DRAWINGS The above-mentioned and other objects,features and advantages of this invention will become more apparcut, andthe invention itself will be best understood, by giving reference to thefollowing description of preferred embodiments of this invention whentaken in conjunction with the accompanying drawings, in which:

FIG. 1 is a block diagram of an embodiment of the electronic musicalinstrument according to this invention;

FIGS. 2A and 2B show examples of controlling waveforms concerning theembodiment of this invention;

FIG. 3 is a circuit diagram of an example of the voltage-controlledoscillator VCO;

FIG, 4 is a block diagram of the main portion of another embodiment ofthe electronic musical instrument according to this invention;

FIG. 5 is a circuit diagram of a pitch controlling circuit in theelectronic musical instrument;

FIG. 6 is a block diagram of a key assigner of the electronic musicalinstrument; and

FIG. 7 is a circuit diagram of a concrete example of a key assigner.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to clarifythe invention disclosed herein, an embodiment according to thisinvention will be described hereinafter by referring to FIG. 1.

In the arrangement illustrated in FIG. 1, a keyboard section 10constituting a music-playing section including, for example, a keyboardor the like produces a signal with a given voltage level correspondingto the depressed key. The voltage signal from the keyboard section 10 iscoupled, in parallel, to first and second voltagecontrolledvariable-frequency oscillators 2a and 2b (hereinafter abbreviated asVCO) to derive the tone source signals corresponding to the depressedkey from each of the VCOs respectively. The tone source signal from theVCO's 2a and 2b are applied to voltagecontrolled variable filters 3a and3b (hereinafter abbreviated as VCF) for effecting tone-coloring and thento voltage-controlled variable-gain amplifiers 4a and 4b (hereinafterabbreviated as VCA) for envelopecontrolling the tonesignal. In the abovemanner, the musical tone signal producing circuit is formed of the firstand second sub-musical tone synthesizer arrangements a and 5h. Numeral5a represents members 211, 2a, 3a, 3a, 4a and 4a of FIG. I, andsimilarly 5h represents the members 2b, 2b, 3b, 3b. 4b and 4h. Themusical tone signals from the first and second submusical tonesynthesizer arrangements are synthesized by a resistor 6 so that theresultant tone signal is derived through a sliding terminal of theresistor 6. This synthesized tone signal is then amplified appropriatelyin an amplifier 7 and is supplied to a speaker system 8 to voice aperformance sound therefrom.

Waveform-generators 2a, 2b, 3a, 3b, 4a, and 4b are provided for the VCOs2a and 2b, the VCFs 3a and 3b, and the VCAs 4a and 412, respectively, tocontrol them with voltage waveforms generated therefrom. These waveformgenerators 2a 4 h are controlled by the waveform controlling circuits 6aand 6b, and produce control waveform signals, varying in voltage levelwith time, in response to the key operation signal derived from thekeyboard section I0, i.e. the'trigger signal including key-depressedsignal which is generated upon the depression ofa key and key-releasedsignal which is produced upon the release of the key, in accordance withthe instructions from the waveform controlling circuits 6a and 6b theterm instructions is used to mean voltage signals representingquantities for determining the transient times and the voltage levels ofthe controlling waveforms (cf. FIGS. 2A and 28). Details of this partare described in the copending U.S. patent application Ser. No. 457,646(Hiyoshi et al) which is commonly assigned with the instant application,since the main part of this copending application is to control thetransient times and the voltage levels of the controlling waveforms withsignal voltages.

FIGS. 2A and 2B show examples of the controlling voltage waveformsobtained from the waveform generators 2a. 2b 4a, 4b. The controllingwaveform shown in FIG. 2A is for the tone pitch and the tone colorcontrol and is applied to the VCOs 2a and 2b, and the VCFs 3a and 3b.The controlling waveform is first triggered by the trigger signal fromthe keyboard section upon the depression of a key, and then shows asharp build-up in the attack time starting from the initial level whichis lower than the normal level and ending in the attack level which ishigher than the normal level, and next decays down to the normal levelin the first decay time, sustains this normal level till the key isreleased, and finally decays down to the initial level in the seconddecay time after the key is released. When the control waveform signalis coupled to the VCOs 2a and 2b, the normal level (normal frequency) isset by the voltage signal from the keyboard section 10. The controllingwaveform builds up rapidly upon the key depression so that the frequencyof the tone source signal, rapidly increases from a frequency somewhatlower than the normal level (normal frequency) to the attack level of afrequency somewhat higher than the normal level. The normal frequencysignal can be obtained after the first decay time. At the time ofkeyreleased, the frequency is decreased from the normal frequency levelduring the second decay time, and consequently the oscillation signal iscut off. That is, an attacking tone source signal with a frequencysomewhat higher than the normal level is obtained at the keydepressedtime, and thereafter the frequency is varied as shown by the waveformshown in FIG. 2A. Thus, a tone signal having a tone pitch modified asthe waveform shown in FIG. 2A as shown in the figure is provided bysimply depressing a key.

Similarly, in the case of the VCFs 3a and 3b, the cutoff frequency isvaried in such a manner as the waveform shown in FIG. 2A. for example,so that higher harmonies are increased especially at the time of thekeydepressed, and the cut-off frequency is decreased after the keyrelease, so that the musical sound ceases softly. In this way, the tonecoloring is modified.

Here, a polarity reversing control may be provided for the controllingwaveforms for the VCOs and the VCFs so that the polarity of thecontrolling waveform can be reversed.

The control of the VCAs 4a and 4b is the envelope control of theamplitude of the musical tone signals derived from the VCFs 3a and 3b bya controlling waveform as shown by the curve shown in FIG. 2B. Namely,the amplitude increases from the normal level and varies after thecontrolling waveform. In this case, the normal level is the cut-offlevel.

The waveform controlling circuits 6a and 6b including resistor circuitsor switch circuits are provided for the respective musical tonesynthesizer arrangements to set and memorize the information such as theattack level, the initial level, the attack time, the first decay time,the second decay time. and the polarity for controlling the VCOs and theVCAs and the information for controlling the VCAs, such as the sustainlevel, the attack time. the first decay time, the second decay time, fordetermining the shape of the controlling waveforms. The waveformcontrolling circuit is the invention of another U.S. application (Ser.No. 457,646) as described above, before which there has been nopertinent prior art. The information can be switched and modified togenerate desired signal waveforms.

FIG. 3 shows an example of the concrete configuration of the VCO,wherein the voltage signal from the keyboard section 10 is applied froma terminal 33 and is read-out through a high input impedance buffer 35after-being memorized in a capacitor 34. Furthermore, the voltage signalis coupled with the control waveform derived from a terminal 36 and isconverted into a current signal by a voltage-controlled converter 37.The current derived from the voltage-current converter 37 changes thevoltage of a capacitor 39 which is interconnected between a power supply38 and the converter circuit 37. The voltage across the capacitor 39 isapplied to a Schmitt trigger circuit 41 to trigger the transistor 42into a conducting state when it reaches a predetermined value. Theconducting transistor forms a discharging circuit for the capacitor 39.The charging and discharging of the capacitor 39 are repeated to providean oscillating output from an output terminal 43, corresponding to thecycle of the charging and discharging. Thus, a tone signal is provided.

In this electronic musical instrument as described above, the musicaltone signals are independently produced corresponding to the depressionof a key in the musical tone signal producing circuits 5a and 5b, andare extremely rich in variations because the tone pitch and the tonecolor vary with time. For example. if the information signals in thewaveform-controlling circuits 6a and 6b are set differently with respectto the initial value. etc.. the musical tone signals having differentvariations in the tone pitch and the tone color will be obtained in therespective tone signal producing circuits, synthesized into a compositetone signal applied to a voicing system to produce coupler effect.

Modified embodiments of the electronic musical instrument according tothis invention will be described by referring to FIGS. 4, 5, 6 and 7. v

A key assigner 11 is illustrated in FIGS. 4 and 6 and is disposedbetween the keyboard section l0'and the musical tone'signal synthesizerarrangement 13a, and

is directly connected to them through the key switches."

This key assigner 11 has, however, the functions of ap plying thevoltage signals from the keyboard section to the musical tone producingdevices and of distributing these voltage signals to each of the tonesignal producing devices in accordance with the order of the keydepression, as will be described in conjunction with FIGS. 4, 5, 6 and7.

Referring now to FIG. 6, for example, it will be noted that to a keyassigner 11 consisting of five rows of se lectably connectingcircuitries 11a 110 is connected a keyboard section including a resistornetwork (shown at block for producing a plurality of notenamedetermining voltages and key switches 12a 12 associated with thekeys (not shown) of the keyboard. Also to this key assigner areconnected five musical tone producing devices 13a 13 The key switches12:! 1211 are selectively turned on as the keys on the keyboard sectionare depressed, thereby energizing the key assigner to couple the notename-determining voltage to the musical tone signal producing device.

When plural keys, at most five in this embodiment. are rendered to thestate of being depressed concurrently, then corresponding number of theconnecting circuitries llu 110 of the key assigner 1] are exclusivelycaptivated" accordingly by these depressed keys, one circuitry for onekey, in the order of depression. In this way, the selected number of thenote namedetermining voltages corresponding to the depressed keys aresupplied to the assigned ones of the five musical tone synthesizerarrangements 13:! 130.

Each of the musical tone signal producing devices 13a I30 are providedwith voltage-controlled variable frequency oscillators 14a and 14b(hereinafter abbreviated as VCO) provided in the first and secondsynthesizer sub-arrangements 131 and 132 (these two constituting one setof musical tone synthesizer arrangement 13a shown in FIG. 4) to whichthe voltage signals from the connecting circuitry llu of the keyassigner are supplied to oscillate-the tone source signals withfrequencies determined by the voltage of the inputted signal.,Each ofthe tone source signals is colored into a musical tone signal by thetone coloring circuit comprising voltage-controlled variable filter 15aor 15b (hereinafter abbreviated as VCF). These colored tone signals arethen amplified by voltage-controlled variable gain amplifiers 16a and1612 (hereinafter abbrevi ated as VCA) and combined to supply an outputat an output terminal 17. Accordingly. the musical tone signal producingdevice 13a or I30 comprises the musical tone signal producing circuitsl3] and 132 in the .first and second musical tone sub-synthesizerarrangements as stated above and the voltage waveform signal from eachof the waveform generators 18a, 18b. l9u. 19b, 20a, and'20h forcontrolling the tone pitch, the tone color and the envelope areconnected to the \/'(Os 14a. 14b, the VCFs 15a, 15/2, and the VCAs 16a,16b, respectively. The waveform generators 18a, lXb. 19a. 1912.200 and20/; receive the trigger signal produced by a key upon the keydepression or the key release through thecorresponding key assigner forproducing the controlling waveforms. The shapes of these controllingwaveforms are determined by the information variables supplied from thewaveform controlling circuits 21a and 21!), similar to the embodimentdescribed above. For example, the oscillation frequency of the VCO 14ais controlled by the voltage signal supplied from the depressed keythrough the key assigner corresponding to the tone pitch of thedepressed key and the controlling voltage waveform supplied from thewaveform generator 18a, to providea tone source signal with a frequencyvarying with time following the depression of the key.

Furthermore, the tone-coloring is effected by the VCF 15a in accordancewith its cut-off frequency and the tone color is varied with time, inresponse to the cut-off frequency variation. The envelope of the tonesignal is variably controlled by the VCA 1611. In other words, thewaveform-controlling circuit 2] provides the details of the control forthe tone pitch, the tone color and the sound volume.

Since two waveform-controlling circuits 21a and 21b, in this embodiment,are provided for controlling the musical tone signal producing circuits131 and 132, although a similar signal voltage is applied from the keyassigners to the circuits 131 and 132 in the first and second musicaltone subsynthesizer arrangements, the musical tone signals obtainedbecome different for different subarrangements. Two kinds of musicaltone signals having pitches which are different by a predeterminedinterval are produced concurrently upon the depression of a key, and areconverted to a mixed audible sound. The voltage signals from the pitchcontrol circuits 22:1 and 22b are applied to the VCOs 14a and 14b tocontrol variably the pitch of the tone source signal corresponding tothe instructions from pitch setters 21(- and 2111 in the waveformcontrolling device 21.

According to a more detailed description, for example, when the VCO 1411includes, as illustrated in FIG. 5, a capacitor 23 for memorizing thevoltage signal determining the tone pitch and supplied through the keyassigner. a buffer 24 of high input impedance for reading-out thevoltage across the capacitor 23, and an oscillator 25 for receiving thevoltage signal read out by the buffer 24, the voltage signal from thepitch control circuit 22:: which is composed of a voltage dividingcircuit including resistors is superposed on the voltage sig nal readout from the buffer 24. The pitch control circuit 2211 can select or seta coupler tone pitch such as 2, 4 by using the pitch setter 2lccomprising a dial member or the like. The controlling waveform from thewaveform generator 18a is also superposed to the output voltage signal.The musical tone signal producing devices 131 and I32 thus provide tonesignals in an arbitrarily selected coupler relation which then form aperformance sound of very rich musical quality.

lf a key switch 12b is turned on while holding the key switch 121! on,"the key assigner llh which has the second priority order following thekey assigner llu is captivated and the voltage signal corresponding tothe key switch 12b is applied to the musical tone signal producingcircuit 13b.

When multiple keys are operated simultaneously, the musical tone signalproducing devices 13a are selectively'connected to the connectingcircuitries I la 1 la, and the musical tone signal producing deviceswhich are selected produce the desired musical tone signal and supply adesired musical tone through the sound-producing system having a speaker(not shown). Letter D indicates a delay circuit which can be inserted inthe trigger signal circuit.

FIG. 7 is a circuit diagram showing the internal details of that portionof the key assigner ll corresponding to the key switch 120 for thesimplicity of explanation.

A drive control circuit for relays 30a 30 including transistors 27, 28and 29 is provided in each of the connecting circuitries lla to Hecorresponding to the key switch 120, and the relays 30a to 30e areconnected to the collector of the transistor 29 to actuate the relayswhen the transistor 29 is rendered conductive. The collector of thistransistor 29 is connected to the base of the transistor 31 which isprovided in all of the connecting circuitries excepting lle to renderthe transistor 31 non-conductive by lowering the potential of the baseof the transistor 31 as a result of the transistor 29 being in its onstate. The collector of the transistor 27 and the emitters of thetransistors 28 and 29 are grounded, in combination, to the ground lineof the connecting circuitry 11a through the key switch 120 in the manneras shown. In the connecting circuitries 11b to 11], the combined lead,in turn, is connected to the collector of the transistor 3] of theconnecting circuitries 11a to 1111 in the prior stage. With reference tothe connecting circuitry He, the emitters of the transistors 27 to 29are, in combination, connected to the collector of the transistor 31 inthe connecting circuitry 1111. If the key switch 120 is turned on whenno other key is depressed, the ground circuit of the transistors 27 to29 in the connecting circuitry Il a and each of the transistors 27 to 29is rendered conductive to trigger the relay 30. Accordingly, a contact32a of the relay 30a is actuated and the voltage signal is derived froman output terminal 33a by the voltage divider circuit including theresistor R corresponding to the key switch 120 and is applied to themusical tone signal producing device 13a. In such condition, the base ofthe transistor 31 is set at a low potential by rendering the transistor29 conductive and is set to non-conduction. As a result, the groundcircuit of the connecting circuitries l lb to He is not formed,accordingly the signal due to the operation of the key switch 12b is notapplied to other musical tone signal producing devices 1312 to 13?.

If another key switch has been already turned on before the key switch120 is turned on, the connecting circuitry Ila for the turned-on keyswitch 120 is already put in the selected condition in the same manneras described above, consequently the transistor 27 in the correspondingcircuit is driven into the conductive state. Therefore, the potential ofthe terminal 26a is set at a decreased level with respect to theotherwise normal potential. Accordingly, the transistor 27 in theconnecting circuitry llu is not energized, and if the key switch 12(- isturned on, the relay 30a is not energized.

Since the ground circuit of the transistor 31 is formed and the positivebias voltage is applied to the base of the transistor 31 through therelay 3011 by the turningon of the key switch 12c, the transistor 3] isrendered conductive to form the ground circuit of the transistors 27 to29 in the connecting circuitry 1 lb provided in the next stage. Thisdemonstrates that the key switch 12(- captivates the connectingcircuitry [lb and serves to couple the signal voltage corresponding tothe key switch l2c from output terminal 33/; to the musical tone signalproducing device l3h by the actuationof the contact 32b due to theactuation of the relay 30/).

Thus, when plural key switches are concurrently turned on. theconnecting circuitries 11a to He are captivated in accordance with theorder of the turningon of the key switches, and the voltage signalcorresponding to each of the turned-on key switches can be separatelyand respectively delivered to the respective musical tone signalproducing devices.

According to this invention as described above, the modifications andchanges of the musical sound can be adjusted as desired or be variablyswitched to improve the performance of the electronic musical instrumenteffectively.

Furthermore, the electronic musical instrument according to thisinvention including the combination of a monophonic electronic musicalinstrument can produce desired coupler effect. Moreover, by adopting theaforesaid key assigner, there can be materialized an electronic musicalinstrument in the poliphonic form.

The musical tone signal producing circuits in the first and secondsub-musical tone synthesizer arrangements have been described inconjunction with the embodiments. It is to be noted, however, that thenumber of the synthesizer arrangements can be increased, and thesynthesizing method of the musical tone signals which are derived fromeach of the synthesizer arrangements canbe arbitrarily altered to obtainfiner performance sound.

I claim:

1. An electronic musical instrument comprising,

a playing keyboard section including a plurality of keys for producing avoltage signal determining the tone pitch of a depressed key;

at, least one musical tone signal synthesizing means connected to saidkeys and comprising a plurality of circuits each connected to saidplaying keyboard section and each connected in parallel with each other,and combining means connected to the output'of each of said circuits forcombining the outputs of said circuits, each of said circuits includinga voltage-controlled, variable-frequency oscillator connected to thekeyboard section and generating a tone signal corresponding to andresponsive to said voltage signal, a voltage-controlled,frequency-variable filter connected to the output of saidvoltage-controlled, frequency-variable oscillator, a first controllingwaveform generator connected to said voltage-controlled,frequency-variable oscillator for generating a controlling voltagewaveform which controls the frequency of the tone signal generated fromsaid oscillator, a second controlling waveform generator connected tosaid voltagecontrolled. frequency-variable filter for generating acontrolling voltage waveform which controls the cut-off frequency ofsaid filter, and a waveform controlling circuit connected to said firstand said second waveform generators independently of said keyboardsection for supplying voltage information to said generators, therebydetermining the shapes of said controlling waveforms.

2. An electronic musical instrument as claimed in claim I, in which saidcombining means is a variable resistor for variably adding the musicaltone signals from the respective circuits.

3. An electronic musical instrument according to claim 1.. in which atleast one of said circuits further comprises a pitch controllerconnected to the voltagecontrolled. frequency-variable oscillator forcontrolling the oscillation frequency of the oscillator in apredetermined manner so as to give a coupler effect to the output of thecombining means.

4. An electronic musical instrument according to claim 1, in which eachof said circuits further comprises a voltage-controlled amplifierconnected to said voltage-controlled filter for imparting an envelope tothe tone signal su-plied from said voltage-controlled filter, and athird controlling waveform generator connected to said amplifier forgenerating a controlling voltage waveform which controls the envelope ofthe tone signal, and supplying voltage information to said thirdwaveform generator.

5. An electronic musical instrument according to claim 1, in which thenumber of said musical tone signal synthesizing means is at least two,and the electronic musical instrument further comprises a key assignerconnected between said keyboard section and said respective tone signalsynthesizing means.

6. An electronic musical instrument comprising:

a playing keyboard section to produce a signal having atone-pitch-determining voltage signal representing the note pitch of thedepressed key of the keyboard; a plurality of voltage-controlled.variablefrequency oscillators to receive in parallel fashion, saidsignal from the playing keyboard section to produce tone source signalsrespectively in response thereto, a plurality of voltage-controlledvariable filters arranged to receive said respective tone source signalsfrom said oscillators and to convert said tone source signals intomusical tone signals by coloring the tone; a sound-producing device toadditively convert the tone source signals received from said variablefilters into audible sound; a plurality of waveform generators connectedcorrespondingly to the respective oscillators and the respectivevariable filters to produce control voltages with a given waveformconstituted by a voltage waveform varying with time for controlling thetone pitch and the tone color; and a plurality of waveform controllingcircuits for controlling the waveform generators respectivelyindependently of each other.

1. An electronic musical instrument comprising, a playing keyboardsection including a plurality of keys for producing a voltage signaldetermining the tone pitch of a depressed key; at least one musical tonesignal synthesizing means connected to said keys and comprising aplurality of circuits each connected to said playing keyboard sectionand each connected in parallel with each other, and combining meansconnected to the output of each of said circuits for combining theoutputs of said circuits, each of said circuits including avoltage-controlled, variable-frequency oscillator connected to thekeyboard section and generating a tone signal corresponding to andresponsive to said voltage signal, a voltage-controlled,frequency-variable filter connected to the output of saidvoltage-controlled, frequency-variable oscillator, a first controllingwaveform generator connected to said voltage-controlled,frequencyvariable oscillator for generating a controlling voltagewaveform which controls the frequency of the tone signal generated fromsaid oscillator, a second controlling waveform generator connected tosaid voltage-controlled, frequencyvariable filter for generating acontrolling voltage waveform which controls the cut-off frequency ofsaid filter, and a waveform controlling circuit connected to said firstand said second waveform generators independently of said keyboardsection for supplying voltage information to said generators, therebydetermining the shapes of said controlling waveforms.
 2. An electronicmusical instrument as claimed in claim 1, in which said combining meansis a variable resistor for variably adding the musical tone signals fromthe respective circuits.
 3. An electronic musical instrument accordingto claim 1, in which at least one of said circuits further comprises apitch controller connected to the voltage-controlled, frequency-variableoscillator for controlling the oscillation frequency of the oscillatorin a predetermined manner so as to give a coupler effect to the outputof the combining means.
 4. An electronic musical instrument according toclaim 1, in which each of said circuits further comprises avoltage-controlled amplifier connected to said voltage-controlled filterfor imparting an envelope to the tone signal su-plied from saidvoltage-controlled filter, and a third controlling waveform generatorconnected to said amplifier for generating a controlling voltagewaveform which controls the envelope of the tone signal, and supplyingvoltage information to said third wavefoRm generator.
 5. An electronicmusical instrument according to claim 1, in which the number of saidmusical tone signal synthesizing means is at least two, and theelectronic musical instrument further comprises a key assigner connectedbetween said keyboard section and said respective tone signalsynthesizing means.
 6. An electronic musical instrument comprising: aplaying keyboard section to produce a signal having atone-pitch-determining voltage signal representing the note pitch of thedepressed key of the keyboard; a plurality of voltage-controlled,variable-frequency oscillators to receive, in parallel fashion, saidsignal from the playing keyboard section to produce tone source signalsrespectively in response thereto, a plurality of voltage-controlledvariable filters arranged to receive said respective tone source signalsfrom said oscillators and to convert said tone source signals intomusical tone signals by coloring the tone; a sound-producing device toadditively convert the tone source signals received from said variablefilters into audible sound; a plurality of waveform generators connectedcorrespondingly to the respective oscillators and the respectivevariable filters to produce control voltages with a given waveformconstituted by a voltage waveform varying with time for controlling thetone pitch and the tone color; and a plurality of waveform controllingcircuits for controlling the waveform generators respectivelyindependently of each other.